Mossberg 930 gas spring

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Mossberg 930 gas spring

Postby finalflighttx » Mon Aug 05, 2013 8:19 pm

Does anyone know were I can buy one of these I want to use it to modify my 935 to shoot 2 3/4" low brass rounds. I think it is the Blue spring and not the yellow one. I have looked all over brownell's and all over Midway USA and found nothing. I also communicated with Mossberg and got no were either. Any help that you all could give me would be a great help.
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Re: Mossberg 930 gas spring

Postby orphanedcowboy » Mon Aug 05, 2013 10:09 pm

Mossberg is where I go mine. They sent me one for the 930, but I didn't tell them what I was doing, I was replacing a bad spring gouging the magazine tube.

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Re: Mossberg 930 gas spring

Postby finalflighttx » Mon Aug 05, 2013 10:12 pm

how hard was it to replace and how much did you give for it?
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Re: Mossberg 930 gas spring

Postby tenfingergrip » Tue Aug 06, 2013 11:38 am

As I look at the schematic for the 930 and 935, I see no differentiation of the return spring of the 930 or 35. Could you point me to anything which shows that the 930 has a softer spring (blue?) than the 935 (yellow?). Never had my return spring out on my 935 and only use it to shoot 3" or heavy load (1550 fps) 2 3/4" shells. I would, however, be most interested in using the 935 to shoot 2 3/4 sporting clay loads with as I really like the way it points, shoulders and patterns. May be the best patterning gun I've got. Any reference links or written info that says there are springs for light loads in the Mossberg pair 93x?
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Re: Mossberg 930 gas spring

Postby orphanedcowboy » Wed Aug 07, 2013 12:55 am

I made this tool to remove and install the spring. It has a 3/8" square drive on the back side.

I don't know the difference, I found the 930 spring would work by pure accident. I had the 930 torn down to fix the tip of the spring that would have most likely gouged the magazine tube. I also had the 935 torn down cleaning it and had both springs out and thought that this could be a problem if they weren't colored. We'll, brake cleaner removes the paint easily. I tried them in the 930 and the recoil was non-existent with the 935 spring and would not eject 2 3/4" target loads. I then tried them both in the 935 and the gun became 100% with 2 3/4" low brass target loads.

I sent pictures of the spring tip protruding into the bore of the barrel lug and asked if they would just send me the spring and they did.

This was back in the days of Maria answering the numerous calls from the Brian Eno's forum on ordering the non ported barrels. I don't know anyone answering calls there now.

Image

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Re: Mossberg 930 gas spring

Postby tenfingergrip » Wed Aug 07, 2013 7:24 am

Ocowboy,
Please excuse my ignorance, but how in the world would a magazine spring have anything to do with the recoil or ejection of light 2 3/4" shells? I would think that the magazine spring only shoves the next shell into the chamber. Am I missing something on the operation of my 935 that no other guns utilize?

I would assume that the return spring, in the stock, would need to be weaker to allow for lighter loads to push the receiver bolt assembly back far enough to eject the spent shell and load the next. Am I missing something or are we calling the two different springs the wrong name? If the return spring were weaker, the recoil would be heavier as the bolt would "bottom out" on heavier loads every time.

If you look at Mossbergs parts schematic, the 930 and the 935 are both the same return spring.

http://www.gunsourcebyzcl.com/home/Gun-Disassembly-And-Info/shotguns/mossberg-shotguns/mossberg-930-and-935-disassembly/mossberg-930-and-935-diagram
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Re: Mossberg 930 gas spring

Postby tenfingergrip » Wed Aug 07, 2013 7:41 am

OC,
Here's another "theory" for you to help me ponder.....due to the fact that the 935 is overbored, do you think that there is significant gases blowing back, around the wad, never getting to the gas ports to drive the bolt back, therefore not enough pressure to eject the light loads. If that is a contributing factor, would enlarging the gas port hole(s) be sufficient or wise to allow for lighter loads? Only way I can get "light" loads to eject now is load them to at least 1550 fps.

Thanks
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Re: Mossberg 930 gas spring

Postby orphanedcowboy » Wed Aug 07, 2013 12:21 pm

The gas spring inside the barrel lug goes around the magazine tube, if the tip of it has a burr, it will gouge the magazine tube.

I haven't any clue about gasses, blow by, or the effect of over bored barrels on anything other than patterns, the bigger barrels likes bigger shot and proves it on the board.

The only real difference in a 935 & 930 is the barrel and forend. Everything else looks identical to me, I have had them torn down and looked at everything from link pins to bolts, bolt stops, action spring tubes, and even magazine tubes.

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